/*
 * Copyright (c) 2006 Zsolt Szasz <zsolt at lorecraft dot com>
 * 
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package org.lorecraft.routes;

import java.util.List;
import java.util.Map;


/**
 * Defines the interface for a path element
 *
 * @author zsolt at lorecraft dot com
 */
public interface Element {

	/**
	 * Links the passed <code>element</code> to this element
	 * 
	 * @param element the element that will be linked to this element
	 * @return
	 */
	Element link(Element element);

	/**
	 * Validates the current context state, checking if it satisfies 
	 * the constraints imposed by this element
	 * 
	 * @param context
	 */
	void map(ProcessingContext context);

	void getPath(StringBuilder builder, Map<String, String> params, List<String> undefineds);
	
	/**
	 * An <code>Element</code> that doesn't process anything, can act as a
	 * terminator for the chain
	 */
	Element NULL = new Element() {
		
		public Element link(Element element) {
			throw new IllegalStateException();
		}
		
		public void map(ProcessingContext context) {
			// do nothing	
		}
		
		public void getPath(StringBuilder builder, Map<String, String> params, List<String> undefineds) {
			// do nothing	
		}
		
	};

}
